Failed Space Station Computer Spurs Contingency Spacewalk Plans

byElizabeth HowellonApril 12, 2014

A view of the International Space Station as seen by the last departing space shuttle crew, STS-135. Credit: NASA

NASA is preparing a contingency spacewalk to deal with a broken backup computer component on the International Space Station, the agency said in an update Saturday (April 12). While there’s no timeline yet for the spacewalk, the agency must consider carefully when to do it given a cargo ship is supposed to arrive at station on Wednesday.

The SpaceX Dragon spacecraft — already delayed due to an unrelated radar problem — is still scheduled to launch Monday at 4:58 p.m. EDT (8:58 p.m. UTC) to arrive at station two days later. Although the computer controls some robotic systems, NASA added the Canadarm2 that will grapple Dragon has other redundancies in place. The question is if the station itself has enough redundancy for the launch to go forward.

“A final decision on whether to launch Dragon Monday will not be made until another status meeting is conducted Sunday morning,” NASA stated.

The failure poses no risk to the crew and normal station operations are not affected, NASA emphasized. The failure was uncovered Friday “during a routine health check” of a box called EXT-2, which backs up a primary component that sits outside on the S0 truss (near the station’s center).

Expedition 39 commander Koichi Wakata performs maintenance on the Carbon Dioxide Removal Assembly on the International Space Station. Picture taken in April 2014. Credit: NASA

Earlier Saturday, a docked Progress robotic spacecraft boosted the station’s altitude in a planned maneuver to ready for the next Soyuz spacecraft launch, which will carry half of the Expedition 40 crew in May.

If spacewalks do go forward, this would be the second required contingency set required since Luca Parmitano experienced a life-threatening leak in a NASA spacesuit last July. NASA ordered an investigation, received a report in February and has halted all nonessential spacewalks while it addresses the recommendations. (Russian spacewalks in Orlan spacesuits are unaffected.)

The only NASA spacewalks that happened since summer took place in December, when an ammonia pump failure crippled science experiments on station. NASA’s Rick Mastracchio and his now returned-to-Earth crewmate Mike Hopkins performed two contingency spacewalks, successfully replacing the pump. The agency has snorkels and absorbent pads ready for its spacesuits as backup if another leak occurs.

Elizabeth Howell is the senior writer at Universe Today. She also works for Space.com, Space Exploration Network, the NASA Lunar Science Institute, NASA Astrobiology Magazine and LiveScience, among others. Career highlights include watching three shuttle launches, and going on a two-week simulated Mars expedition in rural Utah. You can follow her on Twitter @howellspace or contact her at her website.